Parse Config from toml::Table Directly

[bh2smith]

In #11 we introduced a somewhat hacky serialize-deserialize implementation where were we go

String -> toml::Table -> String -> Config

but we should be able to go straight from Table to Config with try_into

https://users.rust-lang.org/t/how-to-parse-toml-table-into-a-struct/88139/2

Pointed out here: #11 (comment)